考虑以下方案(为了更好地理解我的问题)。
如您所见,我正在考虑一个由填充包围的列表 View 。现在,如果用户按下一个列表 View 项,那么我提供的操作就是浅蓝色背景色。现在,我的应用程序正在处理onTouch事件本身,以确定诸如
这是我的代码。
public boolean onTouch(View v, MotionEvent event) {
if(v == null)
{
mSwipeDetected = Action.None;
return false;
}
switch (event.getActionMasked()) {
case MotionEvent.ACTION_DOWN: {
downX = event.getRawX();
downY = event.getRawY();
mSwipeDetected = Action.Start;
// Find the child view that was touched (perform a hit test)
Rect rect = new Rect();
int childCount = listView.getChildCount();
int[] listViewCoords = new int[2];
listView.getLocationOnScreen(listViewCoords);
int x = (int) event.getRawX() - listViewCoords[0];
int y = (int) event.getRawY() - listViewCoords[1];
View child;
for (int i = 0; i < childCount; i++) {
child = listView.getChildAt(i);
child.getHitRect(rect);
if (rect.contains(x, y)) {
mDownView = child;
break;
}
}
return false; // allow other events like Click to be processed
}
case MotionEvent.ACTION_MOVE: {
upX = event.getRawX();
upY = event.getRawY();
float deltaX=0,deltaY=0;
deltaX = downX - upX;
deltaY = downY - upY;
if(deltaY < VERTICAL_MIN_DISTANCE)
{
setTranslationX(mDownView, -(deltaX));
setAlpha(mDownView, Math.max(0f, Math.min(1f, 1f - 2f * Math.abs(deltaX) / listView.getWidth())));
return false;
}
else
{
forceBringBack(v);
}
return false;
}
case MotionEvent.ACTION_UP:
{
stopX = event.getX();
float stopValueY = event.getRawY() - downY;
float stopValue = stopX - downX;
if(!mDownView.isPressed())
{
forceBringBack(mDownView);
return false;
}
boolean dismiss = false;
boolean dismissRight = false;
if(Math.abs(stopValue)<10)
{
mSwipeDetected = Action.Start;
}
else
{
mSwipeDetected = Action.None;
}
String log = "";
Log.d(log, "Here is Y" + Math.abs(stopValueY));
Log.d(log, "First Comparison of Stop Value > with/4" + (Math.abs(stopValue) > (listView.getWidth() /4)));
Log.d(log, "Second Comparison " + (Math.abs(stopValueY)<VERTICAL_MIN_DISTANCE));
Log.d(log, "Action Detected is " + mSwipeDetected + " with Stop Value " + stopValue);
if((Math.abs(stopValue) > (listView.getWidth() /4))&&(Math.abs(stopValueY)<VERTICAL_MIN_DISTANCE))
{
dismiss = true;
dismissRight = stopValue > 0;
if(stopValue>0)
{
mSwipeDetected = Action.LR;
}
else
mSwipeDetected = Action.RL;
}
Log.d(log, "Action Detected is " + mSwipeDetected + " with Stop Value after dissmiss" + stopValue);
if(dismiss)
{
if(dismissRight)
mSwipeDetected = Action.LR;
else
mSwipeDetected = Action.RL;
animate(mDownView)
.translationX(dismissRight ? listView.getWidth() : - listView.getWidth())
.alpha(0)
.setDuration(mAnimationTime)
.setListener(new AnimatorListenerAdapter() {
public void onAnimationEnd(Animator animation)
{
}
});
}
else
{
animate(mDownView)
.translationX(0)
.alpha(1)
.setDuration(mAnimationTime)
.setListener(null);
}
break;
}
}
return false;
}
如您所见,我在MotionEvent.ACTION_UP中确定已执行的 Action ,并相应地设置Enum Action的值。如果用户未越过列表 View 边界,则此逻辑就像一个 super 按钮。
现在,如果用户在滑动(或专门滑动)沿着列表项移动手指时从蓝色变为橙色,则MotionEvent.ACTION_UP将不会提供给listview,这将导致我的代码无法做出决定,并且是由于translationX ()方法和setAlpha(),因为在这种情况下没有确定操作,因此该特定列表项将变为空白。
问题不会在这里停止,因为,我并不是每次都对 View 进行膨胀,所以每次导致同一空的white/white列表项多次出现时,同一translationX()行也会膨胀。
有什么办法可以做到,即使我没有遇到MotionEvent.ACTION_UP,我仍然可以做出决定?
最佳答案
您应该在return true;
中添加case MotionEvent.ACTION_DOWN:
,以便对MotionEvent.ACTION_UP
进行处理。
如View.OnTouchListener所述:
MotionEvent.ACTION_UP
在MotionEvent.ACTION_DOWN
发生之前不会被调用,对此的合理解释是,如果ACTION_UP
从未出现过,就不可能出现ACTION_DOWN
。
此逻辑使开发人员可以在ACTION_DOWN
之后阻止其他事件。
关于android - 不调用MotionEvent.ACTION_UP,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/15799839/